1. Field of the Invention
The present invention relates to a vane-type rotary pump, and more particularly to the structure of its side housing.
2. Description of the Prior Art
A conventional vane-type rotary pump is constructed such that a rotor is rotatably installed in the central housing, eccentric to the central housing; a vane is slidable in a vane groove provided in the rotor; a fluid is drawn into a work chamber constituted between the rotor and the central housing or between the rotor and a rotary sleeve installed in the central housing; and after being compressed or expanded, the fluid is exhausted.
Both ends of the central housing are flanked with side housings and the rotor is rotatably supported by these side housings through a bearing.
In a vane-type rotary pump of such a structure the side housings, which are usually fabricated of cast iron, have the drawback of being very heavy. Recently an attempt has been made to fabricate the entire housing of a light metal or a light alloy for the sake of achieving weight reduction.
However, when the side housings are fabricated of a light metal like aluminum or of a light alloy like an aluminum alloy or a magnesium alloy, the shaft housing to hold the bearing, which is required to be particularly strong, lacks strength and durability tends to become strained or deformed, raising the problem of having the ablity to support the rotor with high presicion.